Motor-starting apparatus



April 13,1926.v

I l v v C. D. AINSWORTH rMOTOR `STARTING APPARATUS v Filed Nov. 6. 1923,Th1/6777er,

Patented Apr. 13, 192' Unirse .eter

CHESTER T). AINSWGR' IPE, CIF W'LLASTON, MASSACHSETTS, ASSGNGR, BYI/IESNE ASSIGNMENTS, TO CONDIT 'LLCTRECA'L MANUFACTURNG CORPORATION, 0FBOS- TON, MASSACHUSETTS, A CORFORA'IN OF MASSACHUSETTS.

MOTGR-STARTING APPARATUS.

Application led November 6, 1923.

T all whom, it may concern:

Be it known that I, CHESTER D. Ainswonrrr, a citizen oit the UnitedStates, rosiding;` at Vo-llaston, in the county of Nortolk and State ofMassachusetts, have invented an Improvement in Motor-Starting Apparatus,of which the following is a specification.

This invention relates to apparatus and systems tor starting electricmotors.

A relatively large electric motor may take many times its normal fullload runningjr current when it is first brought up to normalrunuing'speed and it connected directly to the line tor starting, maycause considcrable disturbance to the line` For this reason appropriatemotor starting apparatus is o-r may be provided which is adapted toreduce line disturbance during the starting of the motor.

The motor starting apparatus usually includes a starting switch and anindependent running switch. The starting switch is adapted to be closedfirst and to connect the motor to the line through a transformer or theequivalent whereby to reduce the voltage on the motor at the instant ot'starting. After the motor has been brought up to speed the startingswitch is adapted to be opened and the running switch closed where by toconnect the motor directly to the line and exclude the transformer.

An object ct this invention is the proviw sion ot means to govern theclosing' et the running switch automatically so that the running switchcan net bc closed until the motor has been brought up to about itsnormal running speed and the starting` current has dropped to somepredetermined low value. In carryingout this cbject ot the invention, Imay provide means governed by the starting current to lock the runningvswitch against closing and said means may be so arranged that when thestarting current has dropped to a predetermined value, as normal fullload, it will operatepto ref lease the lock on the running switch, andthereby permit the running switch to close andthe motor te he cennecteddirectly to i die Serial No. 673,199.

A further object oi the invention is generally to improve theconstruction and operation ot motor starting apparatus and sys-' tems.

Fig. 1 is a diagran'imatic representation 55, ot the motor startingapparatus and system embodying the invention.

Fig. 2 is a detailed elevation partly insection ot a portion ot theoperating mechanism ot a switch with which the invention 00 isassociated.

F ig. 3 is a sectional view taken along line 3*.3 of Fig. 2.

The motor starting apparatus and system embodied in this invention mayinclude a 05 switch 10 which is adapted to connect the line 1l with anautotranstormer 12 or equivalent device whereby to energize the trans-vformer.` A starting,- switch 13 may serve to connect intermediate tapsot the ante-transformer with circuit leads 14, which leads may extend tothe motor, not shown.

The switch 10 and the starting switch 13 maybe mechanicallyinterconnected as by the rod 13a whereby both switches may be 75 openedor closed simultaneously and both switches may be herein termed thestarting switch.

A running switch 15 is provided to connect the motor directly to theline ll and exclude the auto-transformer 12 when the running switch 15is closed. In starting they motor, the switches 10- and 13 are rstclosed and the motor is connected to the line through theauto-transformer and supplied with a reduced potential. VJ hen the motorhas been brought up to speed the switches 10 and 13 are adapted to beopened and the switch 15 is adapted to be closed and the motor maythereby be connected directly to 00 the line.

This invention may be associated with many types ot motor starting`apparatus, as automatically operated apparatus but, for purposes ofsimplicity, itis herewith described in connection with inanually-opeianated apparatus.J y l A switc 'iicll adapted tor this inve t1 maybetenderly ser fornita in" mechanism.

Decemberl 13, i922, and Figs. 2 and 3 illustrate certain details ot theswitch operating Vllhe starting switch and the running switch inay besubstantially alike although this is not essential. Each switch inaycoinprise the tace plate 20, the lower end ot which is torined toprovide a co-il coinpartnient 2l. Tripping coils Q2 inay be received insaid.coinpartinent and a third coil E23 inay also be received in saidcoin-- partinent andthe function ot said third coil 23 will hereinafterbe niore lully set forth. Each coil inay be provided with a core orplunger 2l which, when the coil is suli'iciently energized, is adaptedto be inoved upwardly and strike against a trip pin 25. Saidtrip pin isextended upwardly troni within the coil and through a pedestal 2o and istorined with an enlarged and grooved head Q7 at its upper end. iltriangularly shaped tripping` plate is disposed'above the coilcompartment andinay be torined with' notches Q9 therein into which thegrooved heads 27 ol said tripping pins are adapted to be looselyreceived. The ar4 rangement is or inay be such that when any one oitsaid tripping pins is elevated it serves corresjiiondingly to elevatethe trip` ping plate, said tripping plate being rotated about the othertwo pins as ulcruins, or, it all oi said pins are elevated, they allserve to inove the tripping plates bodily upward for the purpose oftripping the switch'I The switch operating mechanism'includes anoperating handle 30 which inay be pivoted at 31 to the rontvwall of thecoil coinpartinent. A latch 32 inay be arranged to engage said handlewhen it is inoved into a vertical position or in a positioncorresponding with the closed condition of the switch and thereby holdthe switch closed. Said latch inay be elevated manually to perinit thehandle to be nioved outwardly away 'liroin the 'tace plate or into aposition corresponding to the. open position. ol the switch. iin arin353 is or'inay'be pivoted'at 3l concentrically with said operatingvhandle 30 and an operating link or rod 3G inay` be pivoted to said arinand extend to the movable contact ineuibers ot the switch. Means are orniay be providedto connect said handle St) reloasingly with said a-rin"75, whereby the switch inay be opened and said ari'n inay be nioved toa switch-open position independently ol a corresponding nioveinent withthe switch operating. handle SO Said ineans inay include a latch 258,which latch inay be pivoted to a bracket 39 ot the operating. handle 80.S' id latch is' adaptedto engage a projection as the latch roller allot' said arni 35 and the arrangement or inay be such that when saidlatch is in engageinent with said roller7 as indicated in Fig. 2, saidarin may be nioved with said handle E() between switch-open andswitch-closed positions and when said latch 38 is inoved into adisengaged position with said latch roller 40, said arin 35 inay be treeto inove into switch-open position independently ot the handle. Saidlatch 38 is adapted to be tripped by the tripping plate S and, lor thispurpose, inay have a depending ear which is adapted to be disposed aboveand in a. position to be engaged and elevated by said tripping plate..lt is apparent that an upward inovenicnt ot the tripping plate, due tothe energiza-tion ot one o't the coils 22, or the coil Q3, will causethe disengagement oit the latch Ylfroin the roller et() and thereby perinit the switch to open independently ot the corresponding niovenient etthe operating handle.

hleans are preferably provided to interconnect the mechanisms et' thestarting and running switches so that but one switch can be closed atatiine and when the running` switch is closed, the starting switch inustbe opened. Any suitable torni oli'interlocking inechan'isin inay beprovided. As here shown, the inechanisin inay coinprise theinterlocliing rod Said rodinay extend be tween the arins 35 olf thestarting and running switches and may be provided with elongated slots5l and 52 in the ends thereof. The starting switch arni inay be providedwith a projection as the pin 53 which .is adaptedt-o be received withinthe slot 'llhe running switch arin inay be provided with a siinilarprojection as the pin 54 which is adapted to be received within the slotThe arrangement is or may be such that il the starting switch is closedand the running switch is inoved toward closed position, the inoveinentthereof will cause the starting switch to be opened. For this purpose,the latch on the starting handle corresponding to' the latch on theruiming han lle inay be on'iitted so that the starting` switch inust beheld rnanually inclosed position while the niotor is brought up tospeed.

In accordance with this invention, lf provide ineans to prevent theclosing ot the running switch until the inotor has been brought up tospeed or at least until the starting current has been reduced to a valuecorresponding about with the nornial lull load running value. Saidnieans inay include a current transformer GO which trans- 'lorincr inaybe associated with the circuit including the starting switch lil and areranged to be energized by the starting current. Said currenttransformerr inay be arranged to energize the tripping coil 28associated with the runningA switch l5 insuch a inanner as to hold thetripping plate ot said running` switch in elevated Yposition and therebyprevent the closing o't'the switch untilithe current has fallen to apredetermined low value. For this purpose, an excess current relay 62may be arranged in lll.l

the circuit leads 63 and in series with the secondary of the currenttransformer and said coil 23. Said excess current relay is or may bearranged to have relatively low resist-ance and also be so arrangedthat, when the current in the current transformer 60 is at somepredeterminedV low value, its movable member 64 is in a position tobridge the stationary contact members 65 and thereby shunt the trip coil23 and prevent current passing through said coil. lVhen, however, t-hestarting switch is operated and a heavy current passes through the motorsaid excess current relay is adapted to be energized by the currenttransformer to elevate its movable bridgingmember 64 and break theconnection between its stationary Contact members whereby to cause thecurrent to flow from said current transformer through the tripping coil23 and thereby raise the tripping plate of the running switch andprevent the running switch from being closed.

It will be noted that the connections ot the excess current relay aresuch that when sutiicient current tlows through the coil 23, thebridging member 64 of said relay is maintained in elevated position andfree from bridging contact with the stationary contact members 65. lhenthe motor has been brought up to speed and the starting current hasdropped to the normal running current or some other predeterminedreduced value, said excess current relay is arranged to beinsufficiently energized whereby to permit the bridging member 64;thereof to drop and shunt the trip coil 23 thereby to lower the tripplate of the running switch. The running switch may then be closed andconnect the motor directly to the line and exclude the auto-transformer.For certain purposes, the excess current relay may be omitted and thetripping coil 23 connected directly to the current transtormer.V

lVhen the apparatus is associated with manually controlled starting andrunmng switches visual means are preferably pro-` vided to indicate tothe operator the proper time to close the ruiming switch. Said means mayinclude a target of some distinctive color visibly displayed. As hereshown, said target 70 is applied to the lower end ot' the plunger of thecoil 23, see Fig. i2. lVhen said target is in an elevated posit-ion, itserves as an indication that the motor has not yet attained its normalruiming speed and the running switch should not be closed. lVhen,however, said target drops, it indicates to the operator that therunning switch may be closed.

The invention may be otherwise modilied without departing from thespirit thereof.

I claim:

1. Motor starting apparatus including manually operable starting andrunning switches and means rendered eiliectivc'liiy an excessive motorcurrent to prevent the closing o the running switch. I

2. Motor starting apparatus including a starting switch free formovement in a closing direction and a running switch and means governedby the motor startingcurrent to prevent the closing of the runningswitch.

3. Motor startingapparatus including a starting switch and a runningswitch and means associated with the starting switch arranged to holdthe running switch against closing until the motor starting current isat a predetermined value. f

4. Motor starting apparatus including independently operable startingand running switches, interlocking means arranged to hold either switchopen when the other switch is closed, and means governed by the speed ofthe motor to prevent the'closing of the ruiming switch.

5. Motor starting apparatus including independently operable startingand running switches, interlocking means arranged to hold either 'switchopen when the other switch is closed, and means governed by the motorstarting current to disable the running switch an'd prevent the closingthereof.

6. Motor starting apparatus including a starting switch, a runningswitch, interlocking mechanism arranged to hold either switch open whenthe other switch is closed, and means governed by the motor startingcurr-ent to disable the running switch and prevent the closing thereofuntil the starting current has dropped to a predetermined value. l

7. Motor starting apparatus including independently operable startingand running switches, interlocking means arranged to. hold either switchopen whenl the other switch is closed, and means energized by the motorcurrent arranged to disable the running switch to prevent the closingthereof until the starting current has dropped to a predetermined'value.

S. Motor starting apparatus including a manually-operated startingswitch, aI manually-operated running switch and visual means governed bythe motor starting current to indicate the proper time for opening thestarting switch and closing the rainning switch. i l

9. Motor starting apparatus including a starting switch, a runningswitch, a coil arranged to be energized by current traversing thestarting switch to disable the running switch, and a relay energized bythe current traversing the starting switch arranged to govern theoperation of said coil.

l0. Motor starting apparatus includino1 a starting switch, a runningswitch havin@a locking means arranged to hold the switci in closedposition, and means governed by the motor starting current arranged todisable said locking means and prevent the closing oit' the runningswitch until the motor starting current has dropped to a predeterminedlow value.

ll. Motor starting apparatus including a starting switch, arunningswitch having operating mechanism, an operating member and meansreleasingly connecting said operating member' and mechanism, whereby topermit said operating member to close the switch, and means governed bythe current traversing the starting switch to disable said connectingmeans and prevent the closing of the running switch.

1Q. Motor startingapparatus including a starting switch, a ruimingswitch having operating mechanism, an operating member, a latchconnecting said member and vmechanism releasingly, a tripping devicearranged to be moved to actnate said latch and release the connectionbetween said operating member and mechanism, and means governed by. thecurrent traversing the starting switch arranged to operate said trippingdevice and said latch and prevent the closing of the running switch.

In testimony whereof, l have signed my namepto this specication.

CHESTER D. AINSWORTH.

